A new plasticating unit package with extreme abrasion resistance to accommodate today’s highly filled molding and extrusion compounds was presented at NPE2015 by Nordson Polymer Processing Systems, New Castle, Pa. The new package combines two existing Nordson Xaloy products—X8000 screw encapsulation and X800 barrel inlay. X8000 is a nickel-based alloy with high tungsten carbide content that is applied to the entire screw surface using a two-step method that achieves a metallurgical bond rather than the purely mechanical bond formed by standard coatings of this type, Nordson says. What’s more, the X8000 coating is twice as thick as typical coatings.
The X800 barrel inlay is also a nickel alloy with tungsten carbide, which is said to be more wear resistant than iron-based, iron-chromium, or nickel-cobalt alloys.
The accompanying photo shows results of wear testing on a competitive carbide coating (top), with poor adhesion and chipping, versus the relatively undamaged X800 coating (bottom).